The present invention relates to methods and apparatuses for sealing a vessel. More particularly, the present invention relates to methods and apparatuses for protecting a seal using a captured gas volume.
Pressure is an important parameter in many modern industrial and technological processes. In manufacturing, for example, many fluids may be pressurized for the purpose of transporting, ejecting, spraying, applying force, and the like. In particular, photolithography systems that employ extreme ultraviolet (EUV) light for exposing wafers often generate their EUV light by irradiating molten targets (for example tin targets) with laser light. The molten tin targets are pressurized at a high pressure (typically in the range of thousands of PSI) and delivered from a molten tin reservoir to the irradiation site. In a typical scenario, the tin droplets are ejected out of the nozzle of a droplet generator system. The molten target material delivery system that delivers the molten target material (e.g., tin) from one or more molten target material reservoirs to the droplet generator system often employs one or more pressure vessels in order to help dampen vibration and smooth out the pressure profile during the startup phase, for example. These pressure vessels require seals capable of operating across a wide range of temperatures and pressures. Embodiments of the invention are directed to protecting the seals of vessels such as (without limitation) the pressure vessels employed in the molten target material delivery system of a photolithography tool.